SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db4805e55e13c843bdf09f3283f190817803c31ef6ba6d4a9688ce3a75a70c50' 
  AND token = 'vtAUi2k+eMLtD31mQ9OstuAguolViFQ1Jbj3H4ak5W8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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