SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0add07a7b60b6c2b745058b5b00054db81b8235c7b6bbfc66e606fac7dbf5970' 
  AND token = 'SwAAH8PhwCViEQJtJ1W1Q8QZf6yiynCxwd6QwvLlVhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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