SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bed9dd6483054ca970b8049324922cbeee590db3558571bda262dbae6c5dc0c1' 
  AND token = 'K6in7GcXjd5OGQCMNJ5ESvAY94oQyqT8hEZLuOLNbwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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