SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd649940b3e577d72cda46baf77ea91a317df1e7dafc5197fdf64e153b4e1b7fd' 
  AND token = 'fCwu6B+ILbWpRVfmef89TfKl6JJUgAy2oaUPbP49afA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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