SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25468bc3c9a303f9d14cf6cf5505f017281bb5fa78c5ac65c36c2c1f4ed0734d' 
  AND token = 'ytCmQZnhVvuluI3I1ucGFOv6pniUYZ9tjsaRzD+z61w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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