SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7660d2a296909c1a64fd5ec2749014a489e37ad2922b0952caf6c025cd163c30' 
  AND token = '6hhCbu+GJQ5sXi3rhiLkL6hGhoTsavrXzY/zZ/qW8Bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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