SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '987b42f75c011589f123c9267f56a35de3e70dd41818a4e0ed1a1cf740a3796f' 
  AND token = 'J5l6E6SCvF/TmZXw6ephCyzW++jhZmi43w3GmNxlhzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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