SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a92beb2bb9e261ab16906854a3da69410cf0e317e6fe98584660f68161fb644f' 
  AND token = '9rLYx3Xa6Hj8PmAwEXHmQhOGToegQ/4RaK/5qyIHpcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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