SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '227d130e23313421e12509bfbaf4727eb76ec31e195cedf05099853f71d57d11' 
  AND token = '8sA6QpFywI+6QkctGAsORQOTFiQdNOypfQfmfYF36NI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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