SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9375d7a5ceb317a2366872f1114cd6ca4eadd9668ae2222f80fd019977f2ca39' 
  AND token = 'cMZg0DnaavX36Hjnw7mL990UIFJz3o8Tnq7xqNjFUJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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