SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d8a35d63f17cc793a437616aca795339467765997010a08d64a64c663a42cb9' 
  AND token = '4VIvRQL4lQrsjuD/lu2+U4bthAVuvltrJZjaiUcuk/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}