SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7262b90374ec194b1922a9fd3e8302fd7877f496ad7a0ebce9b2d6c6b309beca' 
  AND token = 'MYz/SSvb2pwnbNI2pukgLAlBKniWN0a4fJ5RkiNqOMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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