SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15b26bffe5b7f9c4551a26a988cf3451897f48d80b7faa9cba971a78228405c7' 
  AND token = 'wojoCKURB/hq/ZE+Xjbjd4bka4YN1NGsdt7nPPfXX4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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