SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e50ac68728e6f5f7528669eaf393224061fdf64bbcd27f82eed1535ea3cb9879' 
  AND token = 'gNKB/oC4WlDjSK1/elbbTkb0nLdhQz0vDHD9cXj8zis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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