SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce036b95a313d19702c5f5ffdf2ba72542da3571a23b40e93d8443b6921b9306' 
  AND token = 'UFLtK04lKwYsVnxRkEyj6hHGyJuPaWzqYNYbyXs46sE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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