SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a4ea648fe9fe6a7bb3992fee3559ea45791d51ee65c9d8d5d6a0476192f43d5' 
  AND token = 'oPJVwGjt7U/TDKBD+HrZkpzAabm7i9hjC2PiGjoP32A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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