SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3c254e1f56cf4e055acc4e32be896ebeadd0b1b45a66d04298ea3a9f4abadaf' 
  AND token = 'se2zBlaLZDFoAYJ5gWzOUWkNoQR8umU9IHyfUt13LiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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