SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8d41cc7de23c87417d23ddbed9c00af521be1eb57785251101c07b232ef2733' 
  AND token = '3NpVPs03F4xJSF8TDm6SHxXmDZZGsfj8alF7BnnJicg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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