SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a70798fc8c884780df6e97ca1dcbe37c7865b842aac7a6941f20b2c8cf208b0e' 
  AND token = 'ObUnUKmqZwzuV4lzQ/WM5Jiw7ARSW02oFfE7KKWVE9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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