SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c9dd78863fb069be024cbe12a79a1def6a77ac9d4ad7eb030a08be6d1f94cdb' 
  AND token = '9MHqozpDGD4ndjFuqEfAp3TZ3xjJhfhxhUVjx8U24fI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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