SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b9bc12766370080d97485fcdb60fdf05e6c5ff2f9f5e9c7a365a84efd724e97d' 
  AND token = '6ZFG+INPiYSL+v1KEfZTBPAl00P4e1/4WrDDDTCVJCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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