SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d90173d0d9c7948284f725accfb98017b43bac462fbbab829e4956df064d608' 
  AND token = 'NpLEJ9RThqVYXzDb6UKJOWGD2wZgzwVE5/1w4Uu0lOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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