SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '908c433e212ff894c932ef29ef835a0e18a33b09e5683c04c892bcf17ec53c1f' 
  AND token = 'qA038q7nrDdTjtElRD7HOh7rXw5ZAWFVsWPLNNPwEh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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