SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2b3c304514d1501ce1a0d04c8391bc55968debf51e23e8116db903f261f25ee' 
  AND token = 'EzLJgvp1XHr9ENFW4DxPcLmsICswkZXwCACg4OuKWqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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