SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d2f743ca4cfebad381c42cf04178cd0cb94d509ec9854abc937a1f055eacdba' 
  AND token = '3g6ld00pRGTlZlM0CbRdlRHXxbF9R/+M1phARRspOlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}