SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '329a040c744aa393d33eef0ba484a1b8b36b65acf37207b1d213ec21fc4f3400' 
  AND token = 'HWpn1e3cGvyBAiPHFPvJd6CI71QEiIBcBaLqiEe91v4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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