SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a52395464cbcbba254f259472911efe498f1cca5a714f50d17ee4e68736f0fd3' 
  AND token = 'KEQi1JGgGJakUhXLL4RLrKSVwxh6WtS0u15x7BRX5+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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