SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d3b5efcfdef615ed98b475b62e9636f62d407ed514c417829a299307366c354' 
  AND token = 'JH6mdSZ/pVpMUOTWOX+y8xIV8d1YFGVlUVpGPp32hG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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