SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '050bfeace6862ed4bd29c6fa28bc222b2b85b19e6d65df18655da5acecf66691' 
  AND token = 'LcKXMXE7yektwQWOmQiVmPHO5qu1pZTNlFbkMeLSjq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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