SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcca2f900ae6338ff7aaab1b63d275ce206a7f46e838b7dbafddf5b336e0739f' 
  AND token = 'D5h/w6hDQvVwgC0gtRftYB4R7OFO2tJ7uwUCuBKXMmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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