SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c59a7a8e827e744f783425f9ccd53922b02091706254beaa50b03ae9b66e92e' 
  AND token = 'ZlXG0qrmROGonZWKp/yqFoVqgXp19uOuJLuq09tz9v4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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