SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '447263254a7573d6bba1f12549bfde0a4fe3018976857a1589bcc54b555f72b5' 
  AND token = 'w3mOsxIfp2em7KD9/NbaHyhCpSf2DhQVLkjxQoYU++w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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