SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4e37902bb201ede13f306da88c14e7b431cb8233089bdaf5bae00ca28589cb7' 
  AND token = '3GBZ8nYUaU/wE1NvyI1BOMCur+TShaTtM2QubBCLVsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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