SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f97c48bfb0593078e086789740a954da1298f13d1a5ae0dbc9a35840e7ddac07' 
  AND token = 'g/f/1Mm6nvSUpLlnXSXLyrjCOZsKPmh1UQuET6MhCXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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