SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c23dea0d0c4d0d992a5de033772d67cc88e38534405d71662268253124e2746e' 
  AND token = '0AK14LnJAeQuyBnpcQJlDRN6KPX9rYWMDAL+wuG2hg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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