SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4604a970a211c4ba8aac9647e64703ff9cbe459bbae34afe4aba6975296e9d7' 
  AND token = 'PHcDRch5wEjx9fbODfkGTiyzRNdFqmzhDa0xcbqoMgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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