SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecf9ae57671d4ecdf0e74e1aefc8cc1a2dac1dad29aa75940500ad67560feed3' 
  AND token = 'APk2F93BQ+tOVgE6c7mhuGJ3VnL8G3xfVZ77wDJkyOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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