SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2473da16aeba56b9cb309566b4950934ed218e4b6bfcd96b9e61a86e15835556' 
  AND token = 'v8T0Nu82jTo2ETg2CfHZSBVroX2HOAEcgYhgkZ+UFLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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