SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6132bff1923b0e6338802c21b98cd2b8240bffa49a1e8c12d119511d3ac5a73' 
  AND token = 'HYMpIzdE580NANyxy7ccxg7SIrPuWDJIWQbKU1QvPyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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