SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2de9abe3a5adad47ca7dce85fef9698fa1003335c6e95febae1cce3f5413151' 
  AND token = 'WGwzHtAa1IkY/iaEK2JJn5bNqmHHA4kO+dWa1OsoDF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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