SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd46b2ad5b29fed99d65ddce117293d7267d55103e07b803f39d63714368f21b5' 
  AND token = 'C35jVlfBWsOy5Cs0DiTnu9eL4kwyUI2bHkH3F8VWUAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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