SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3f8c5c2ec72612185887d1ba2fe6ba8febddd24b778749e8d009d888b089545d' 
  AND token = 'dg9IGhRl6CiaGKrS7pojEtBxqzYOH4Zmv9SXyp8YWV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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