SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b181c4e68fe775b9025aa38672c6114d38f7b6de9f95deb01e74fae4309c8def' 
  AND token = 'zpm1VwtP32zWzwKSldQjqblgEzji/PC4ZEz5sLhRQAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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