SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '46b0fa70a51fae361a2b3c58bf06468b994807c50f5c4a93d663162f44a2c692' 
  AND token = 'k0Qxvv7Nna827y8NCJ3q/4AQKrv+oRCBmygKRGMTj6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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