SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9783f4c6980f7dddeb70e608bd247a4af06f2f5671ccf29bc32cd226822374e' 
  AND token = 'NMv3jLX/SCWOsHNnn7Y4wIMD+vMiuGtmRZNYh/41X2Y=' 
  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"
    }
  }
}