SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcc5da412219c923696f96e40a163fe789bacfe32c5ca182cb8ddcd83a524235' 
  AND token = '2fCUIWyvwl3D19RhWUxHPIRERZURt7ViIJi0YEVtGUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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