SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3946a619c82eebef28571416e923b70976d76607b856468cbbdee182035bc65b' 
  AND token = '7phfHdQr3vMJTvOXhw2pwX/ZQ1B4do9MNYC3vgsQtNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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