SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe82c976b35c170224e076be39b2feb5bf52ea29c4f07f5cd00c3855a4ff0e8' 
  AND token = 'hKOhVJtsm1GrkhNQ36Z/ladh1VQWi+NgHFzFeKOau+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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