SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5298cbb3e15661ed6fa487c469e6739b92fcb98f58988c0bfebbae11886572a' 
  AND token = 'LgoHAps1hLkzPAGPlAXGTFiVddGsZXdvvSOXsfBoYjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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