SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8707dfec9c3d95e9387919884fa10f9592fc2c9fd5f44d454b829bcd9af40ef' 
  AND token = 'mQvSEzi+Lb9SSTwXFtPm9hzb0OhUga6aHTHQuEuJ4Xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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