SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36a71094ce45cf9add0cb7e8a221c2a210873a7a3bb78cf5034ca4255090a845' 
  AND token = 'sN87FKtTAv5Elzrn0aQoWv9cFooNjIKD/5pgEh99ei0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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