SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ee3b8876d17819d030be8b897c5d4f34589c9ed24aea034e2d48f957171c59e' 
  AND token = 'rclzO2xFypGqVPZnUVjUvJxAc2KI//Pce/i4FZDl+2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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