SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af7a49c5d7b6d8571fc87643d58c333a6c44c9aee02eaec6b3c91755cd3453b6' 
  AND token = 'wBipFB0+ZpYGLHRqE3ptRKHMqyvezhTBZOqRfPp6VsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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