SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b721a2ebf1bad64869a1f41043b094b8c22f78e70684123cab14ad689d5fada' 
  AND token = 'kcNQG4hST6Jc5fs6bLnJuTOGseHfWY9ZQX164vjix8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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