SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '217e551d48a19a44c4f959f273db7e6c6eb178c3bbeec395990ce62446b1f820' 
  AND token = 'FjbgJwuE1fJ9hmVaqS6G5ICLCixzm7u8Rav6cRCcHvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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