SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30801c1609be98607d7a185eebb34466716ba91490b309dcf1cd2cdceb288186' 
  AND token = '6uOMNykF7Y6qKDiiVSq32D/24lYdxUERlsbdickyPpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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