SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53b15b5aa763df88a665b95b4aac4e517bdd3aad31adc8eafbf359c9e23a6111' 
  AND token = 'qx9BSk5GtQIRgYxMfCwgqsTy3OVlcOvYosndfYqP59o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}