SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e384354f5ae7fa452143fbb500441afc5dac9083c7cb97fe4b0a321b64e2c56c' 
  AND token = 'nJfCnQEjTwV4ATnZ34xaA70RHjAW9sD4sAHjaU5ALsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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