SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86c49fed5fed920fc99fc2e6683c9c75dbe23f4780b30061270138db379ffc67' 
  AND token = 'BdkydhqMnTJwweumLyu58iIS1quUZzpL3/d3pXTgBoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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