SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbe465ef35fb1e80b4bdddce2952857435fac4b5c780281ae427eff1a78a4875' 
  AND token = 'mr4UhzpjFFfqnV1RqSQl1ygfg/kkIhIeD+9asCYOJqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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