SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '727e84c9414ac203fccc6df08437534e1ee02afcbc32658080ef0d9f36539bc2' 
  AND token = 'GiYFjddHwgjuQq/+DfHav4TKBB8Ct+rTMyn28W1l4Cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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