SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79528276c9d825769acadbc16fb0a3fbac49dba200c0a735979cb01c88c6302d' 
  AND token = 'N50sPHR7Dvu4mBQRlxLFdQsWRa7WRTZylVreZTDGF30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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