SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0acc46d5cedadd2e513e3bc0fbeb55947860c983913d17e8764806299465ca9' 
  AND token = 'C8oAY1iuivKftXfdgVfwICdzDwqG5Z/+BYlGGOgk6gE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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