SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a8490f6694a1b8054450c95f81f72a557f6a56df88877c3341788f49abc22e4' 
  AND token = 'BSrcLITATNpIuGgXgZM751XwnoGShLQAqkBjNqPfOJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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