SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87b3a92c5ea0d2dd68b04bd1ad6840eee84731180cdd6919c6c2c9e596c5585b' 
  AND token = 'IFrjzL/vNA3SiaDbT/e3WJa7wKVV8HOI9kHkwpBtbJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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