SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e1d37db0da07ac7ca4743aa86ebc8215db407d7a1240cafcf3839556c867a88' 
  AND token = 'VC/tWeZi5JDYgRoCPsdl4d6/usm16gzjyAn8ppcjzDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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