SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e11fdbc4281a418877d91371fa9cd184e9c7ec92e699277a853a27d21fa1bea' 
  AND token = 'X3SCfpnrOZ2cRjZDzWnOFvtdcV9wmQZ37T/05OIGE00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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