SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f442946db366aeeb99cda3b6959f60b33f4158a2404bbefa5d0312f71d418fe' 
  AND token = 'wIShXWSNdHwsDBhPTtuVgjgAzo7oj0aOKUyx1CPeE/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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