SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6135c0d61911028b7522a3611d3d4209670324434c358814db5fe42d7710d919' 
  AND token = '+UN9UzRPNzyg4dRTsb2EMb6/z428sCIb61NaQRQt+b8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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