SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '471859be8475e82b44f5def8ee8803ee4dba0121cc04d10f60ef05134852de77' 
  AND token = 'QXYPnYJLpyBBgMlziezrDesj9oMvZDK/OtDUqhHiKtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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