SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3387d3947cd8b6d580eb218acc13976c09dae3b9844b890f73f36d3f023902cf' 
  AND token = 'PBg/ravC/kKjzj4wYtfaJcDWcSqST09rU5zxIVq2SPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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