SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b273c3d184224b79d89a7b790fc358a574eca632f8dbf889a25a4d1f58f28eef' 
  AND token = 'BGHOiP7wei5VdbR7L+4OFDkgW0+2rFM/BqKjg3ml5s0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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