SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7be64adc12b7b2a1e60b4abf62940565a63a0a4391afe04d293583a1d9a0f66' 
  AND token = 'OXzkMLTiUvi39jfQOhy+yH5cShSC5l4zpaT39ZZfdR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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