SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdf34a8eb432187a303ab1137a96b7a325d42f4af980ad4443b469b3837ec1ba' 
  AND token = 'tRaYulaML6JUMdSgN1FVW3Uf1rL1Y++iGXUJrGw1IYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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