SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b84cfd0d9de7d7fd2c569e6b35f4eb40402c68cc95718bbd168e451f9450c8c' 
  AND token = 'HvP7ZJxHHviYghxKE9ZSL4lV9zRZJXdcMnHVsIgG3d0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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