SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7611313abf989b6862521b358126e083c20d5e3c170592ada8718c18922ad46f' 
  AND token = 'vavYxv9ek09mtGl00rWysfZMixV5zsgFsWHZkZDc5ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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