SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b7855f4d34ef44a2802514e1c60fcf0f15c3f2d9e7a611694b0ee1e2849bbd41' 
  AND token = 'cEjvS+dbhoqTRJvZqrbyHFGBiky/dI4QwO2m81o4WqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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