SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c6527c74895f19b39593525684c4e48003ae66fd0b076c57789a37a5ae9afb0' 
  AND token = 'rKysjzY+XVi6GpfGKkV6M+7PMYMZsbvpNc8LeFyQjgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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