SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f77473752c402a3e2d160392aabda41ff02882986b13b600ef3276e51d4153b' 
  AND token = 'm0rcbgziDp3U2xKGhj5lvTJtxvXrfOurZcd1UjRW/JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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