SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83d0943e63ea98fdc08aa47daf43fe0dac3fe406f87eb1664cc592089ba78ebb' 
  AND token = 'sy4kdbfClCxtMi69hfEmloSIXMp4iYB667dmOnWhlLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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