SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3719cc81e8108ffb840645403323e2df350e323b7db392c7f2f08b001caaa61f' 
  AND token = 'WeShABgcrTPNqwj6KUy8xNBrGmhjX7B9qpQnF8v/PhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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