SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b15b577979f639dcef1424339d192b70379bdbeca59076017bcd147255bcec6a' 
  AND token = 'j41LiZV0WCUgLYcu2PG9/RegI/3NFgS/zWcAC/9G8og=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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