SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4511e8fb35814af7a8113facf4750d5f7ff802002fc785ead8f054286078d1d4' 
  AND token = 'ZXqoDI3MUSWA/ZmzfqGhI2njLv2Nz4bgemDyCVGJYZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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