SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ea9eb4332ddebed869ce3d1d21427c457f37804a394f986cc4000cfa74c14fe' 
  AND token = 'tIa/AWEmTl4vRB3qIQ8BjOX6XnFEhjQ9dQnaV46OswA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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