SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bab99e4f4eb3c20ba38f32f7c1442a98201d9b9d529818c005a8d1250edf2a71' 
  AND token = 'HUX1VYD1Ixq4bJGgXTJOVgyccnsAoO8Peelq49ovjtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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