SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43099b2c6cc77874d16b6f6279e04c94e38afd68557d9816963a4fbc5591a200' 
  AND token = 'UMMvfmUMsmrpRdpWKoB3jRzwOA0k+sc79CKGYDOEqKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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