SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d660ca7cbe0dc4d6d198730f60ae9f55f6af6254e5cb0a4a4bd9c7fe8ce5737' 
  AND token = 'eH0xCE6MmLRkgQ4gdEecVsJ3atGHsvvCM75PHUHrgHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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