SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b91d3c6529d4ad4572e9ba09126fb4de3b0726daea2aceb6bd73b937105639b' 
  AND token = 'HLPLXiUWcSKKJeQaHNBEPvYOz/MGVVFzW3DufK1VnaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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