SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20f2b0e0ab0114cac5107bfd933c7614fdce2082e44f960cbbe267e57bf67028' 
  AND token = 'eQYxtRO6xGZKJZUMPEPVpdDbT+WB0zwP0HquOGR7ovI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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