SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee4ede03c75d12f9dee94a03144781b00431423f7952f3e7f3d282eeba0d7e19' 
  AND token = 'mK8FXg+zaaKVXySXukcZs9CCTHj0RdN/cEaeNppbslM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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