SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5da5382aef7f81bfd02dcd663b917460ba5a5b4fa49094792436fa33363843d' 
  AND token = 'XgEei8QH2VnWC8K5ysshnJf/+w28/H9zV7JvMNGiUbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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