SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d9ae20ffdafa48924143422700b1a6aa6e1d9ce9a143435d3ec3ccd2e716553' 
  AND token = 'AXgfRZD8WT8ZECWxfWBtQjWApyL7rxnWtmhlKElMGUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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