SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fcb37de877c82b31625d13081450ef05adc425ec649c25afec9372604d6542c' 
  AND token = 'TKyTRHr0fIM5xTrFvTG9ei9e1ONFN8tEXCj+P7aMx1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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