SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fddcde4bca51c69844d3bedd82c4760492fbfed1afba0c543cb2fe19980f034' 
  AND token = 'CZ8ns+E5CKB6MLzVXQ0EZrYBXn7Mv01jj1HphjwVNfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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