SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5f9e65444d562580491731ddf5d05d8d09ffe89fca1d16acfd84bfe8ae0eb44' 
  AND token = '5+YXJKb+oPjf0+5IUGIApmj3UVIa5iKaALgajCwDETY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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