SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5858ed14e425d51702ae91801eaf3320ba4d93b5dac05b076ac2a2cccc72d157' 
  AND token = '7rXpWQedliEJFE1hbRCUjfSbR3xiNrHIxZx/6zYq6RI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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