SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '42469113dc0580861bd9d1950a7dfa72d8c0b0f7326d710e41e56d86fb2e73f5' 
  AND token = 'StGgunE4oWmgEMEwMN/V4LTzUySb9AnqtkT4mXdGE7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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