SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '487440998a397fcb0f975ad8025cac035f2528b74f63aa0c9260364d78a50465' 
  AND token = 'qnvlGK2rn/Jv6j3LPHkD8tf6Twvyt734/DgzGdIVsnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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