SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6760d30d5146f199d1350a8dfe2fea4ce3e31b53fd102c3221315d331d5c6341' 
  AND token = 'elvJIOk9WsMg4tHeXG7k6CfpY/O1wxX0ggKpJHPlN9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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