SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7e61143804bc09a6042fb5e55576428d5be0dcf52d3538b88283642785481ff4' 
  AND token = 'krFxK1y1wcqRoHRhTnPibwn4uBykMHwlw2Gum+CFWq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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