SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07cd8af674b91e34065d427c0aa1d05865542d48936c3988578d7b9083c3af97' 
  AND token = '/q2TRKrGQFtWfJI5ieDTcZPhOB0JzQMfs+He/pI16Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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