SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82774da1d7d51ff65237d3b275cb17a7df34be3ac40f27ec50145f664999f063' 
  AND token = 'fXJz+xUjM41LFIakT9OQE1KVQ293X9UJq+jFj98QbXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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