SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99cc918b25eddccae25f5f62805092f08ae75a389226396ee064c8278f7f5cad' 
  AND token = 'mNRklRsqE8b8uFb8uPKHHxJyF+tSMk/2oPrQ/DZoqsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}