SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8a2fc29d595af29c7e8c549d07f545ea5ebad8b664afbe1b464eebc2f3d60c81' 
  AND token = '/RgQjeBI/EczQF+jhxMX1/5P7voeTOaYHXPj/JMKasw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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