SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9d72f6944a03ee680eaf66d273fa202d1501f122e6fe61a2025998786a9379d' 
  AND token = 'ROPCMv9bPd2Kfjjtwvi/dGtxbusc5uRUd6r/oPXDa/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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