SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90e46d1562292fba1c5ff4fee93feb8786412fa40f44ac087193f1d62d5d25fa' 
  AND token = 'skLU+H6ox55zNHzf6QnPJFjU0YiINgB2w8qrjLmKj3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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