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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33ec9bc60d6e9cdbb056fc7666451ae35e2a2f345b85d76602ab8b2ffd3f7f7a' 
  AND token = 'rUt7PmVPWJJEQlD0Jiz6AgnY2rT5U5SvoLK18YNcKdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}