SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98a49405dde42740fc2aa10250d81497584af7722238f05399f7de603e91ee2d' 
  AND token = 'Bs4LP2a0xiGGar4eCVNy3QKcjKBBeentHXMH0LfPoGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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