SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16ba20f3a3ed8da229e20845861fc018a9843fdcab394ba49c1d06a1d58c1120' 
  AND token = 'F4n82ItTapIUCV6Vfy5HZFbbl54CjLlFUDZ9Iy3c88o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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