SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55651cca53ff63e582fd3ff57877e6ded17bb4581fadd3a97935c6360a2b005d' 
  AND token = '1/iJ3fgzGN/VRqhTXVxdeTpzA29CBfbmszj72DmKuxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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