SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a0f88e3024a2780ec7ef2ec12c7edc1efec285075990466f5e5495ab976413b' 
  AND token = 'gQ7TJeh4fXni/HvqaK3frcKzyOufNCmRgC+BSzQVp4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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