SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89ce2c4d629be30cdc8147db22a241fd84e7f0809361dd98f6c6cda086554cd4' 
  AND token = 'G2RJYHn4Mqy9pPaeAhkKccuOSdF9aTn2UuE2FGDZmvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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