SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c561f2a80fb380204b13ce10d71adc808c0a4d70cc212d2fb1f6ad8c0260ba46' 
  AND token = 'avk8VEdN8b8lU95oI/19z/KvPhUfb0UU6GLnCEDsqRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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