SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9492f82d9c6d576650c47143576622ba789f6c39243edb30f8395b9ea456b39' 
  AND token = 'EfCuTkKpxkhzfGd/AQyWPG102TVJ6jgcjJV1kAai+og=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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