SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd43ee5c4525db0a41b7e612f9dc032dd0312734375d70836116b89e849ad9c54' 
  AND token = 'MluLKvSfq7cXEHi9v6IOKuwfUB5ZcrzZgKmJl2v3aWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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