SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959026f68b11c0a893d774cffc8c6219904f90e4d4785b130a89d07f171814c5' 
  AND token = 'nBs8c/0uQvwbK7taoLqv9mp6hqUo5geGlWKcy2rkC5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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