SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7528532d711a2f2b1489472fcd1bfc2043cae08caa9ddecf50baa8049976266' 
  AND token = 'bj+FfcGiqGMNV7BT7VXbxatERa/Daowe7rZ1SVRFFEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00472

JSON explain

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