SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88f996fe31669183c1f322dda3152829d57aa460b9d48b440d2aa9dd7ea9baab' 
  AND token = 'COxY0u4kXOBDHCXVuLepcI85p2WUph/q7ZgkSH8gr5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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