SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '446463546223e80ff74240b450834a9e014de059bdfc1851a508aa37da2bc680' 
  AND token = '/5Hif7JVi+SgW3yNY/FBw1wUaT6jdR2IVdUyaIYDee8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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